Nemesis theory

I herd of a theory about red or brown dwarf that is a companion star with the Sun.I looked on http://en.wikipedia.org/wiki/Nemesis_%28star%29" [Broken] it doesn't too much about it.
Dose anyone know if there's been any stars that could possible Nemesis or if there's any evidnce of it's existance.

For years we have heard that these are only myths, there was no Golden Age and precession is just a wobbling of the Earth’s axis. Now Lost Star of Myth and Time shows evidence the Ancients were not just weaving fanciful tales - science is on the verge of an amazing discovery - our Sun has a companion star carrying us through a great cycle of stellar influences. If true, it means the Ancients were right and our views of space and time and the history of civilization will never be the same. More than that, it would mean we are now at the dawn of a new age in human development and world conditions.

but I fell asleep during the interview so I really don't remember all that he had to say. Made a nice bedtime story, though!

In terms of the original idea (a small star, or super-Jupiter, in a highly elliptical orbit, stirring up the Oort cloud and so creating mass extinction events here on Earth), it's dead - the periodicity in the fossil record is far from clear, there is no corresponding record of contemporaneous impacts on other solar system bodies, mass extinctions on Earth - with one notable, and possible two or three less notable, exceptions - cannot be tied to any impacts (by any of the usual measures), etc, etc, etc.

In terms of the observational data, it's pretty clear there are no red dwarfs close enough to be in any quasi-stable orbit, nor white dwarfs. Brown dwarfs are not yet fully ruled out, but the region of parameter space they could inhabit, undetected to date, is small.